Number of strings of length n from a 3-symbol alphabet (A,B,C, say) containing at least one "A" and at least two "B"s.
A309000
Number of strings of length n from a 3-symbol alphabet (A,B,C, say) containing at least one "A" and at least two "B"s.
Terms
- a(0) =3a(1) =22a(2) =105a(3) =416a(4) =1491a(5) =5034a(6) =16365a(7) =51892a(8) =161799a(9) =498686a(10) =1524705a(11) =4635528a(12) =14037627a(13) =42391378a(14) =127763925a(15) =384536924a(16) =1156232175a(17) =3474201510a(18) =10434138825a(19) =31326533680a(20) =94029932643a(21) =282194655482a(22) =846802070205
External references
- oeis: A309000